This invention relates to a sheet cutting system and, in particular, to a knife attachment that is interchangeable with a panel saw for attachment to a sheet cutting system.
Systems for cutting sheet material, such as, sheet rock and wood panel have been known for many years.
The prior art mat cutting systems generally use a knife or blade. U.S. Pat. No. 6,283,003 to Hans on et al uses a blade that is held by a blade holder in a cutting head.
U.S. Pat. No. 4,802,399 to Orlon discloses a support for holding a construction size sheet for cutting by a saw attachment on a carriage. The carriage travels on a pair of rails and guide tubes to saw a cut in the work piece.
Saw Tax Mfg. of Actor, Ga., has a construction type cutting system, which uses an ordinary utility knife fastened to a sheet metal bracket. Unfortunately, the attachment is not rigid and does not achieve the desired accuracy in use.
An object of the present invention is to provide a rigid utility knife attachment for commercial graphic arts and construction cutting systems. A further object of the present invention is to provide a utility knife attachment that is easy to assemble, easy to change blades and easy to adjust for depth penetration.
These and other objects of the present invention are fulfilled by a knife attachment that has a base with a front surface and a back surface. The back surface faces a sheet of material held in position adjacent the base that is to be cut or scored. The base has a hole extending between the front and back surfaces. A mounting plate is mounted on the front surface of the base adjacent to the hole. This mounting plate has an extension that is perpendicular to the base and which has a slot that extends from the portion of the extension away from the base towards the base at an acute angle to the base.
A knife holding bracket is attached to the extension of the mounting plate by attaching means, such as a bolt and wing nut, so that the knife holding bracket can be moved along the slot in the extension. A stud may be extended through the slot in the extension of the mounting plate and into the threaded hole in the knife holding bracket to hold it in proper position in relation to the slot. The knife holding bracket has a securing plate, which is parallel to the base and located on that portion of the bracket closest to the hole in the base. This securing plate is attached to a holding plate that is perpendicular to the base and spaced close enough to the knife holding bracket to prevent the knife from moving laterally. A utility knife having an extendible blade is attached to the knife holding bracket by means such as the same bolt and wing nut that attaches the knife holding bracket to the extension of the mounting plate. The knife is disposed between the knife holding bracket and the holding plate of the knife holding bracket. The blade of the knife can be inserted into the hole to the desired depth. The knife has a tab near the blade end of the knife that is spaced from the body of the knife and projects away from the blade end of the knife and can be inserted under the front edge of the securing plate to hold the knife securely. The knife holding bracket and attached knife can be slid along the slot of the extension of the mounting plate so as to determine the depth of penetration of the blade of the knife into the sheet material being cut. This knife is a conventional utility knife, which has a tab on the handle at the blade end which can be used for securing the knife to the knife holding bracket.
It will be seen that the securing plate of the knife holding bracket prevents the knife from moving in a perpendicular fashion in respect to the base unless the knife holding bracket is moved along the slot in the extension of the mounting plate. Preferable a bolt with a wing nut is used to hold the knife to the knife holding bracket and extension of the mounting plate, but can be adjusted to permit the bracket and knife to be moved along the slot to the depth of the knife blade into the material being cut that the operator desires. The wing nut can then be tightened to hold the knife blade in that position. A holding plate located along the edge of the securing plate away from the knife holding bracket at a distance slightly greater than the width of the knife secures the knife from moving side to side. Securing the knife in this manner enables the user to accurately cut the piece of material.